In this paper, we describe the formation of macroporous silicon (MPS) formed anodically polarized on n type Si (100) substrates at a constant current density under front side illumination using two electrolytes, HF/Ethanol and HF/Ethanol/H2O2. The effect of adding H2O2 in the solution on the resulting pores were investigated by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), contact angle measurements and UV-vis spectrophotometry. The results showed that for the anodization conditions the MPS formed in peroxide based (H2O2)/HF/Ethanol solution exhibited structures with larger pore size and different pore morphologies depending on the etching time than those formed in HF/Ethanol. The pore density and the pore size of the MPS samples increased with the etching time. The infrared absorption spectrum (FTIR) carried out on the freshly prepared sample indicates that the MPS contains Si-Hx bonds which decrease with increasing the etching time. Finally, measurements of contact angle indicate that the formed MPS samples are highly hydrophobic.